The rising prevalence of obesity in the U.S. over the past several decades and the accompanying spread of adverse long-ranging health effects pose serious public health and economic consequences. While a genetic contribution to obesity is well-established, genetic factors underlying individual susceptibility to common obesity have modest effects, which can be amplified considerably in the presence of certain triggering environmental factors. Approximately two-thirds of women of reproductive age now enter pregnancy at a high body mass index, and the majority of women experience pregnancy-associated weight gains in excess of Institute of Medicine guidelines, leading to increased perinatal and chronic health risks for both mother and child. The increased prevalence of obesity among women of reproductive age is reflected in a concomitant increase in the prevalence of gestational diabetes (GDM), which confers additional increased risk of adverse maternal and child health outcomes. Limited previous intervention research has indicated modest improvement in short-term maternal diet and gestational weight gain, with little evidence of long-term adherence. The well-documented inadequacies of these and traditional weight-loss interventions relying on existing health behavior paradigms suggest the need for innovations that allow for a shift in the theoretical framework underlying the determinants of eating behavior. Recent findings from basic research in neuroscience suggest that the brain reward response to highly palatable foods is a critical element that is currently absent in current theoretical frameworks. Individuals vary with respect to their ?food reward responsivity?, which refers to susceptibility to the effects of food and eating on the brain reward system. Simultaneously, foods vary with respect to their ?reinforcement value?, which refers to the degree to which foods activate the brain reward system. Whereas certain foods elicit a normative food reward response that is sensitive to homeostatic regulation of appetite, it is hypothesized that ?hyperpalatable? foods, which elicit exceptionally pronounced activation of the brain reward system, may blunt this sensitivity, leading to hedonic, non-homeostatic overeating characterized by food intake beyond energetic needs. Repeated consumption of hyperpalatable foods reinforces the brain food reward response and culminates in neurological changes similar to those observed with drugs of abuse. However, this rapidly-expanding body of work has not yet been incorporated into population-based research. Research to date on food reward responsivity and food reinforcement value has been conducted primarily in small samples in the general population. However, to date, no studies have examined these constructs among pregnant women. While it is known that most women gain more weight than recommended and many do not return to their pre-pregnancy weight, there is insufficient data on individual determinants of dietary intake and weight change during and after pregnancy. Understanding the association of food reward responsivity and food reinforcement value with dietary intake and weight change during pregnancy and postpartum may be informative for the development of clinical and public health interventions that promote optimal diet and weight in this population.